1. Field of the Invention
This invention relates to an improvement in a structure for electrically connecting a high-voltage circuit board to an electric component in an image forming apparatus.
2. Description of the Related Art
Generally, an image forming apparatus is provided with circuit boards adapted to apply a high voltage to various electric components which need supply of a high voltage. Examples of such electric components are a charging unit for charging the surface of a photosensitive drum, a developing unit for supplying toner onto the drum surface, a transferring unit for transferring a toner image formed on the drum surface onto a copy sheet, and a separating unit for separating the toner image carrying sheet from the photosensitive drum. Hereinafter, the circuit board for supplying a high voltage to the electric component is called xe2x80x9chigh-voltage circuit boardxe2x80x9d. The high-voltage circuit board is generally located away from the corresponding electric component to keep the electric component from being affected by an electromagnetic wave generated by the high-voltage circuit board. For the supply of a high voltage from the high-voltage circuit board to a electric component, the electric component is connected, by electric wires, with contact terminals which are in contact with the high-voltage circuit board.
In the conventional arrangement described above in which the high-voltage circuit board are located away from the corresponding ones of the electric components in such a manner that each of the electric components and the corresponding high-voltage circuit board are connected by electric wires, failure in electric conduction is likely to occur due to incomplete coupling of connectors upon connection of the electric wires to the electric component or the high-voltage circuit board, or incomplete fastening of the contact terminal. Furthermore, the conventional arrangement requires the high-voltage circuit board and the electric wires to be coated with a shielding member to keep peripheral devices including the electric component, from being adversely affected by an electromagnetic wave generated by the high-voltage circuit board and the electric wires, whereby the number of parts constituting the image forming apparatus resultantly increases, lowering efficiency in assembling the image forming apparatus, and raising production cost of the image forming apparatus.
In view of the above, it is an object of the present invention to provide an image forming apparatus in which a high voltage circuit board is electrically connected with an electric component in a sophisticated way.
It is another object of the present invention to provide an image forming apparatus which includes a structure for electrically connecting high-voltage circuit board with an electric component of the image forming apparatus for supplying high-voltage to the electric component, with the structure being less liable to incomplete connection or failure in electric conduction.
It is still another object of the present invention to provide an image forming apparatus in which a high-voltage circuit board is electrically connected with an electric component, with the influence of electromagnetic wave caused by the high-voltage circuit board being effectively prevented while the circuit board being located relatively close to the electric component.
It is further object of the present invention to provide an improved structure for the electric connection between a high voltage circuit board and an electric component to supply a high voltage from the high-voltage circuit board to the electric component in an image forming apparatus.
It is still further object of the present invention to provide a structure for an electric connection between a high-voltage circuit board and an electric component of an image forming apparatus with the influence of electromagnetic wave caused by the high-voltage circuit board being effectively prevented while the circuit board being located relatively close to the electric component.
According to an aspect of this invention, an image forming apparatus comprises a structure or an assembly for electrically connecting a high-voltage circuit board with an electric component of the image forming apparatus. The structure or assembly includes a circuit board attaching member which holds the high-voltage circuit board, and a contact terminal extending through the circuit board attaching member to be in contact with the high-voltage circuit board and the electric component for the electric connection therebetween.
According to another aspect of the present invention, the contact terminal may have a rod shape and the circuit board attaching member may be formed with a cylindrical guide member having a through hole through which the contact terminal extends.
According to still another aspect of the present invention, a positioning hole is formed on the high-voltage circuit board, and the circuit board attaching member is formed with an engaging portion engageable with the positioning hole to position the high-voltage circuit board relative to the circuit board attaching member.
According to further aspect of the present invention, the structure or assembly for the electric connection may further comprises a grounding member for grounding the high-voltage circuit board, and the circuit board attaching member may include a grounding member holding portion for holding the grounding member thereon, with the grounding member being in contact with the high-voltage circuit board and being exposed out of the circuit board attaching member when the high-voltage circuit board is coupled with the circuit board attaching member.
In the above arrangement, since the high-voltage circuit board and the electric component are directly and electrically connected by the contact terminal, occurrence of inferior electric communication between the high-voltage circuit board and the electric component is suppressed. Further, since the high-voltage circuit board and the contact terminal are mounted on the main body of the image forming apparatus in a state that the circuit board attaching member covers the high-voltage circuit board and the contact terminal when the high-voltage circuit board is allowed to be electrically connected to the electric component, peripheral devices including the electric component are kept from being adversely affected by an electromagnetic wave generated from the high-voltage circuit board. This arrangement enables to dispose the high-voltage circuit board closer to or adjacent to the electric component, which makes it possible to construct a high voltage supply assembly for supplying a high voltage from the high-voltage circuit board to the electric component in a small space. Furthermore, the above arrangement makes it possible to directly and electrically connect the high-voltage circuit board to the electric component by way of the contact terminal without using an electric wire. This arrangement enables to decrease the number of parts required for connecting the high-voltage circuit board to the electric component while keeping the peripheral devices including the electric component from being adversely affected by an electromagnetic wave generated by the high-voltage circuit board.
These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawing.